Machines on the personal server will not spawn

I just checked Unity of the vehicles and all looks fine, so my only guess is that there is a ID conflict with other mods.

I don't know how to check that for a server but in the game there is an Error log under workshop.

Someone was kind enough to test the mod on their private server and all vehicles spawned in. So it seems like it's your servers issue, if you want you can send me the server console log and i'll try to find what's the problem.